Establishment risk from pet-trade freshwater turtles in the European Union

The pet-turtle market has grown in recent years and become an important pathway for the introduction of alien species in Europe. The import of Trachemys scripta elegans has been banned by European Commission Regulation due to its species’ expanding territory and negative impact on native species. Since the demand from hobby breeders persists, however, blocking imports of this popular subspecies opens up the possibility for the introduction of other potentially invasive turtles. We determined those turtle species most common in the pet trade within the Czech Republic, which is the most important producer, importer and exporter of ornamental aquatic animals in the EU. The determination of establishment risk for the EU as a whole was then individually evaluated for turtle species based on known establishment models. Chelydra serpentina, Apalone spinifera, Apalone mutica, and Sternotherus odoratus were considered most problematic, because these species have serious establishment risk and are imported to the EU in substantial numbers. Also localities in the EU were identified where probability is highest for establishment of non-native turtles.